1 /* 2 * POSIX message queues filesystem for Linux. 3 * 4 * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl) 5 * Michal Wronski (michal.wronski@gmail.com) 6 * 7 * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com) 8 * Lockless receive & send, fd based notify: 9 * Manfred Spraul (manfred@colorfullife.com) 10 * 11 * Audit: George Wilson (ltcgcw@us.ibm.com) 12 * 13 * This file is released under the GPL. 14 */ 15 16 #include <linux/capability.h> 17 #include <linux/init.h> 18 #include <linux/pagemap.h> 19 #include <linux/file.h> 20 #include <linux/mount.h> 21 #include <linux/namei.h> 22 #include <linux/sysctl.h> 23 #include <linux/poll.h> 24 #include <linux/mqueue.h> 25 #include <linux/msg.h> 26 #include <linux/skbuff.h> 27 #include <linux/vmalloc.h> 28 #include <linux/netlink.h> 29 #include <linux/syscalls.h> 30 #include <linux/audit.h> 31 #include <linux/signal.h> 32 #include <linux/mutex.h> 33 #include <linux/nsproxy.h> 34 #include <linux/pid.h> 35 #include <linux/ipc_namespace.h> 36 #include <linux/user_namespace.h> 37 #include <linux/slab.h> 38 39 #include <net/sock.h> 40 #include "util.h" 41 42 #define MQUEUE_MAGIC 0x19800202 43 #define DIRENT_SIZE 20 44 #define FILENT_SIZE 80 45 46 #define SEND 0 47 #define RECV 1 48 49 #define STATE_NONE 0 50 #define STATE_READY 1 51 52 struct posix_msg_tree_node { 53 struct rb_node rb_node; 54 struct list_head msg_list; 55 int priority; 56 }; 57 58 struct ext_wait_queue { /* queue of sleeping tasks */ 59 struct task_struct *task; 60 struct list_head list; 61 struct msg_msg *msg; /* ptr of loaded message */ 62 int state; /* one of STATE_* values */ 63 }; 64 65 struct mqueue_inode_info { 66 spinlock_t lock; 67 struct inode vfs_inode; 68 wait_queue_head_t wait_q; 69 70 struct rb_root msg_tree; 71 struct posix_msg_tree_node *node_cache; 72 struct mq_attr attr; 73 74 struct sigevent notify; 75 struct pid *notify_owner; 76 struct user_namespace *notify_user_ns; 77 struct user_struct *user; /* user who created, for accounting */ 78 struct sock *notify_sock; 79 struct sk_buff *notify_cookie; 80 81 /* for tasks waiting for free space and messages, respectively */ 82 struct ext_wait_queue e_wait_q[2]; 83 84 unsigned long qsize; /* size of queue in memory (sum of all msgs) */ 85 }; 86 87 static const struct inode_operations mqueue_dir_inode_operations; 88 static const struct file_operations mqueue_file_operations; 89 static const struct super_operations mqueue_super_ops; 90 static void remove_notification(struct mqueue_inode_info *info); 91 92 static struct kmem_cache *mqueue_inode_cachep; 93 94 static struct ctl_table_header *mq_sysctl_table; 95 96 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode) 97 { 98 return container_of(inode, struct mqueue_inode_info, vfs_inode); 99 } 100 101 /* 102 * This routine should be called with the mq_lock held. 103 */ 104 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode) 105 { 106 return get_ipc_ns(inode->i_sb->s_fs_info); 107 } 108 109 static struct ipc_namespace *get_ns_from_inode(struct inode *inode) 110 { 111 struct ipc_namespace *ns; 112 113 spin_lock(&mq_lock); 114 ns = __get_ns_from_inode(inode); 115 spin_unlock(&mq_lock); 116 return ns; 117 } 118 119 /* Auxiliary functions to manipulate messages' list */ 120 static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info) 121 { 122 struct rb_node **p, *parent = NULL; 123 struct posix_msg_tree_node *leaf; 124 125 p = &info->msg_tree.rb_node; 126 while (*p) { 127 parent = *p; 128 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); 129 130 if (likely(leaf->priority == msg->m_type)) 131 goto insert_msg; 132 else if (msg->m_type < leaf->priority) 133 p = &(*p)->rb_left; 134 else 135 p = &(*p)->rb_right; 136 } 137 if (info->node_cache) { 138 leaf = info->node_cache; 139 info->node_cache = NULL; 140 } else { 141 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC); 142 if (!leaf) 143 return -ENOMEM; 144 INIT_LIST_HEAD(&leaf->msg_list); 145 } 146 leaf->priority = msg->m_type; 147 rb_link_node(&leaf->rb_node, parent, p); 148 rb_insert_color(&leaf->rb_node, &info->msg_tree); 149 insert_msg: 150 info->attr.mq_curmsgs++; 151 info->qsize += msg->m_ts; 152 list_add_tail(&msg->m_list, &leaf->msg_list); 153 return 0; 154 } 155 156 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info) 157 { 158 struct rb_node **p, *parent = NULL; 159 struct posix_msg_tree_node *leaf; 160 struct msg_msg *msg; 161 162 try_again: 163 p = &info->msg_tree.rb_node; 164 while (*p) { 165 parent = *p; 166 /* 167 * During insert, low priorities go to the left and high to the 168 * right. On receive, we want the highest priorities first, so 169 * walk all the way to the right. 170 */ 171 p = &(*p)->rb_right; 172 } 173 if (!parent) { 174 if (info->attr.mq_curmsgs) { 175 pr_warn_once("Inconsistency in POSIX message queue, " 176 "no tree element, but supposedly messages " 177 "should exist!\n"); 178 info->attr.mq_curmsgs = 0; 179 } 180 return NULL; 181 } 182 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); 183 if (unlikely(list_empty(&leaf->msg_list))) { 184 pr_warn_once("Inconsistency in POSIX message queue, " 185 "empty leaf node but we haven't implemented " 186 "lazy leaf delete!\n"); 187 rb_erase(&leaf->rb_node, &info->msg_tree); 188 if (info->node_cache) { 189 kfree(leaf); 190 } else { 191 info->node_cache = leaf; 192 } 193 goto try_again; 194 } else { 195 msg = list_first_entry(&leaf->msg_list, 196 struct msg_msg, m_list); 197 list_del(&msg->m_list); 198 if (list_empty(&leaf->msg_list)) { 199 rb_erase(&leaf->rb_node, &info->msg_tree); 200 if (info->node_cache) { 201 kfree(leaf); 202 } else { 203 info->node_cache = leaf; 204 } 205 } 206 } 207 info->attr.mq_curmsgs--; 208 info->qsize -= msg->m_ts; 209 return msg; 210 } 211 212 static struct inode *mqueue_get_inode(struct super_block *sb, 213 struct ipc_namespace *ipc_ns, umode_t mode, 214 struct mq_attr *attr) 215 { 216 struct user_struct *u = current_user(); 217 struct inode *inode; 218 int ret = -ENOMEM; 219 220 inode = new_inode(sb); 221 if (!inode) 222 goto err; 223 224 inode->i_ino = get_next_ino(); 225 inode->i_mode = mode; 226 inode->i_uid = current_fsuid(); 227 inode->i_gid = current_fsgid(); 228 inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode); 229 230 if (S_ISREG(mode)) { 231 struct mqueue_inode_info *info; 232 unsigned long mq_bytes, mq_treesize; 233 234 inode->i_fop = &mqueue_file_operations; 235 inode->i_size = FILENT_SIZE; 236 /* mqueue specific info */ 237 info = MQUEUE_I(inode); 238 spin_lock_init(&info->lock); 239 init_waitqueue_head(&info->wait_q); 240 INIT_LIST_HEAD(&info->e_wait_q[0].list); 241 INIT_LIST_HEAD(&info->e_wait_q[1].list); 242 info->notify_owner = NULL; 243 info->notify_user_ns = NULL; 244 info->qsize = 0; 245 info->user = NULL; /* set when all is ok */ 246 info->msg_tree = RB_ROOT; 247 info->node_cache = NULL; 248 memset(&info->attr, 0, sizeof(info->attr)); 249 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max, 250 ipc_ns->mq_msg_default); 251 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, 252 ipc_ns->mq_msgsize_default); 253 if (attr) { 254 info->attr.mq_maxmsg = attr->mq_maxmsg; 255 info->attr.mq_msgsize = attr->mq_msgsize; 256 } 257 /* 258 * We used to allocate a static array of pointers and account 259 * the size of that array as well as one msg_msg struct per 260 * possible message into the queue size. That's no longer 261 * accurate as the queue is now an rbtree and will grow and 262 * shrink depending on usage patterns. We can, however, still 263 * account one msg_msg struct per message, but the nodes are 264 * allocated depending on priority usage, and most programs 265 * only use one, or a handful, of priorities. However, since 266 * this is pinned memory, we need to assume worst case, so 267 * that means the min(mq_maxmsg, max_priorities) * struct 268 * posix_msg_tree_node. 269 */ 270 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + 271 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * 272 sizeof(struct posix_msg_tree_node); 273 274 mq_bytes = mq_treesize + (info->attr.mq_maxmsg * 275 info->attr.mq_msgsize); 276 277 spin_lock(&mq_lock); 278 if (u->mq_bytes + mq_bytes < u->mq_bytes || 279 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) { 280 spin_unlock(&mq_lock); 281 /* mqueue_evict_inode() releases info->messages */ 282 ret = -EMFILE; 283 goto out_inode; 284 } 285 u->mq_bytes += mq_bytes; 286 spin_unlock(&mq_lock); 287 288 /* all is ok */ 289 info->user = get_uid(u); 290 } else if (S_ISDIR(mode)) { 291 inc_nlink(inode); 292 /* Some things misbehave if size == 0 on a directory */ 293 inode->i_size = 2 * DIRENT_SIZE; 294 inode->i_op = &mqueue_dir_inode_operations; 295 inode->i_fop = &simple_dir_operations; 296 } 297 298 return inode; 299 out_inode: 300 iput(inode); 301 err: 302 return ERR_PTR(ret); 303 } 304 305 static int mqueue_fill_super(struct super_block *sb, void *data, int silent) 306 { 307 struct inode *inode; 308 struct ipc_namespace *ns = sb->s_fs_info; 309 310 sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV; 311 sb->s_blocksize = PAGE_SIZE; 312 sb->s_blocksize_bits = PAGE_SHIFT; 313 sb->s_magic = MQUEUE_MAGIC; 314 sb->s_op = &mqueue_super_ops; 315 316 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL); 317 if (IS_ERR(inode)) 318 return PTR_ERR(inode); 319 320 sb->s_root = d_make_root(inode); 321 if (!sb->s_root) 322 return -ENOMEM; 323 return 0; 324 } 325 326 static struct dentry *mqueue_mount(struct file_system_type *fs_type, 327 int flags, const char *dev_name, 328 void *data) 329 { 330 struct ipc_namespace *ns; 331 if (flags & MS_KERNMOUNT) { 332 ns = data; 333 data = NULL; 334 } else { 335 ns = current->nsproxy->ipc_ns; 336 } 337 return mount_ns(fs_type, flags, data, ns, ns->user_ns, mqueue_fill_super); 338 } 339 340 static void init_once(void *foo) 341 { 342 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo; 343 344 inode_init_once(&p->vfs_inode); 345 } 346 347 static struct inode *mqueue_alloc_inode(struct super_block *sb) 348 { 349 struct mqueue_inode_info *ei; 350 351 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL); 352 if (!ei) 353 return NULL; 354 return &ei->vfs_inode; 355 } 356 357 static void mqueue_i_callback(struct rcu_head *head) 358 { 359 struct inode *inode = container_of(head, struct inode, i_rcu); 360 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode)); 361 } 362 363 static void mqueue_destroy_inode(struct inode *inode) 364 { 365 call_rcu(&inode->i_rcu, mqueue_i_callback); 366 } 367 368 static void mqueue_evict_inode(struct inode *inode) 369 { 370 struct mqueue_inode_info *info; 371 struct user_struct *user; 372 unsigned long mq_bytes, mq_treesize; 373 struct ipc_namespace *ipc_ns; 374 struct msg_msg *msg; 375 376 clear_inode(inode); 377 378 if (S_ISDIR(inode->i_mode)) 379 return; 380 381 ipc_ns = get_ns_from_inode(inode); 382 info = MQUEUE_I(inode); 383 spin_lock(&info->lock); 384 while ((msg = msg_get(info)) != NULL) 385 free_msg(msg); 386 kfree(info->node_cache); 387 spin_unlock(&info->lock); 388 389 /* Total amount of bytes accounted for the mqueue */ 390 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + 391 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * 392 sizeof(struct posix_msg_tree_node); 393 394 mq_bytes = mq_treesize + (info->attr.mq_maxmsg * 395 info->attr.mq_msgsize); 396 397 user = info->user; 398 if (user) { 399 spin_lock(&mq_lock); 400 user->mq_bytes -= mq_bytes; 401 /* 402 * get_ns_from_inode() ensures that the 403 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns 404 * to which we now hold a reference, or it is NULL. 405 * We can't put it here under mq_lock, though. 406 */ 407 if (ipc_ns) 408 ipc_ns->mq_queues_count--; 409 spin_unlock(&mq_lock); 410 free_uid(user); 411 } 412 if (ipc_ns) 413 put_ipc_ns(ipc_ns); 414 } 415 416 static int mqueue_create(struct inode *dir, struct dentry *dentry, 417 umode_t mode, bool excl) 418 { 419 struct inode *inode; 420 struct mq_attr *attr = dentry->d_fsdata; 421 int error; 422 struct ipc_namespace *ipc_ns; 423 424 spin_lock(&mq_lock); 425 ipc_ns = __get_ns_from_inode(dir); 426 if (!ipc_ns) { 427 error = -EACCES; 428 goto out_unlock; 429 } 430 431 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max && 432 !capable(CAP_SYS_RESOURCE)) { 433 error = -ENOSPC; 434 goto out_unlock; 435 } 436 ipc_ns->mq_queues_count++; 437 spin_unlock(&mq_lock); 438 439 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr); 440 if (IS_ERR(inode)) { 441 error = PTR_ERR(inode); 442 spin_lock(&mq_lock); 443 ipc_ns->mq_queues_count--; 444 goto out_unlock; 445 } 446 447 put_ipc_ns(ipc_ns); 448 dir->i_size += DIRENT_SIZE; 449 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir); 450 451 d_instantiate(dentry, inode); 452 dget(dentry); 453 return 0; 454 out_unlock: 455 spin_unlock(&mq_lock); 456 if (ipc_ns) 457 put_ipc_ns(ipc_ns); 458 return error; 459 } 460 461 static int mqueue_unlink(struct inode *dir, struct dentry *dentry) 462 { 463 struct inode *inode = d_inode(dentry); 464 465 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir); 466 dir->i_size -= DIRENT_SIZE; 467 drop_nlink(inode); 468 dput(dentry); 469 return 0; 470 } 471 472 /* 473 * This is routine for system read from queue file. 474 * To avoid mess with doing here some sort of mq_receive we allow 475 * to read only queue size & notification info (the only values 476 * that are interesting from user point of view and aren't accessible 477 * through std routines) 478 */ 479 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data, 480 size_t count, loff_t *off) 481 { 482 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); 483 char buffer[FILENT_SIZE]; 484 ssize_t ret; 485 486 spin_lock(&info->lock); 487 snprintf(buffer, sizeof(buffer), 488 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n", 489 info->qsize, 490 info->notify_owner ? info->notify.sigev_notify : 0, 491 (info->notify_owner && 492 info->notify.sigev_notify == SIGEV_SIGNAL) ? 493 info->notify.sigev_signo : 0, 494 pid_vnr(info->notify_owner)); 495 spin_unlock(&info->lock); 496 buffer[sizeof(buffer)-1] = '\0'; 497 498 ret = simple_read_from_buffer(u_data, count, off, buffer, 499 strlen(buffer)); 500 if (ret <= 0) 501 return ret; 502 503 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp)); 504 return ret; 505 } 506 507 static int mqueue_flush_file(struct file *filp, fl_owner_t id) 508 { 509 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); 510 511 spin_lock(&info->lock); 512 if (task_tgid(current) == info->notify_owner) 513 remove_notification(info); 514 515 spin_unlock(&info->lock); 516 return 0; 517 } 518 519 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab) 520 { 521 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); 522 int retval = 0; 523 524 poll_wait(filp, &info->wait_q, poll_tab); 525 526 spin_lock(&info->lock); 527 if (info->attr.mq_curmsgs) 528 retval = POLLIN | POLLRDNORM; 529 530 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg) 531 retval |= POLLOUT | POLLWRNORM; 532 spin_unlock(&info->lock); 533 534 return retval; 535 } 536 537 /* Adds current to info->e_wait_q[sr] before element with smaller prio */ 538 static void wq_add(struct mqueue_inode_info *info, int sr, 539 struct ext_wait_queue *ewp) 540 { 541 struct ext_wait_queue *walk; 542 543 ewp->task = current; 544 545 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) { 546 if (walk->task->static_prio <= current->static_prio) { 547 list_add_tail(&ewp->list, &walk->list); 548 return; 549 } 550 } 551 list_add_tail(&ewp->list, &info->e_wait_q[sr].list); 552 } 553 554 /* 555 * Puts current task to sleep. Caller must hold queue lock. After return 556 * lock isn't held. 557 * sr: SEND or RECV 558 */ 559 static int wq_sleep(struct mqueue_inode_info *info, int sr, 560 ktime_t *timeout, struct ext_wait_queue *ewp) 561 { 562 int retval; 563 signed long time; 564 565 wq_add(info, sr, ewp); 566 567 for (;;) { 568 __set_current_state(TASK_INTERRUPTIBLE); 569 570 spin_unlock(&info->lock); 571 time = schedule_hrtimeout_range_clock(timeout, 0, 572 HRTIMER_MODE_ABS, CLOCK_REALTIME); 573 574 if (ewp->state == STATE_READY) { 575 retval = 0; 576 goto out; 577 } 578 spin_lock(&info->lock); 579 if (ewp->state == STATE_READY) { 580 retval = 0; 581 goto out_unlock; 582 } 583 if (signal_pending(current)) { 584 retval = -ERESTARTSYS; 585 break; 586 } 587 if (time == 0) { 588 retval = -ETIMEDOUT; 589 break; 590 } 591 } 592 list_del(&ewp->list); 593 out_unlock: 594 spin_unlock(&info->lock); 595 out: 596 return retval; 597 } 598 599 /* 600 * Returns waiting task that should be serviced first or NULL if none exists 601 */ 602 static struct ext_wait_queue *wq_get_first_waiter( 603 struct mqueue_inode_info *info, int sr) 604 { 605 struct list_head *ptr; 606 607 ptr = info->e_wait_q[sr].list.prev; 608 if (ptr == &info->e_wait_q[sr].list) 609 return NULL; 610 return list_entry(ptr, struct ext_wait_queue, list); 611 } 612 613 614 static inline void set_cookie(struct sk_buff *skb, char code) 615 { 616 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code; 617 } 618 619 /* 620 * The next function is only to split too long sys_mq_timedsend 621 */ 622 static void __do_notify(struct mqueue_inode_info *info) 623 { 624 /* notification 625 * invoked when there is registered process and there isn't process 626 * waiting synchronously for message AND state of queue changed from 627 * empty to not empty. Here we are sure that no one is waiting 628 * synchronously. */ 629 if (info->notify_owner && 630 info->attr.mq_curmsgs == 1) { 631 struct siginfo sig_i; 632 switch (info->notify.sigev_notify) { 633 case SIGEV_NONE: 634 break; 635 case SIGEV_SIGNAL: 636 /* sends signal */ 637 638 sig_i.si_signo = info->notify.sigev_signo; 639 sig_i.si_errno = 0; 640 sig_i.si_code = SI_MESGQ; 641 sig_i.si_value = info->notify.sigev_value; 642 /* map current pid/uid into info->owner's namespaces */ 643 rcu_read_lock(); 644 sig_i.si_pid = task_tgid_nr_ns(current, 645 ns_of_pid(info->notify_owner)); 646 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid()); 647 rcu_read_unlock(); 648 649 kill_pid_info(info->notify.sigev_signo, 650 &sig_i, info->notify_owner); 651 break; 652 case SIGEV_THREAD: 653 set_cookie(info->notify_cookie, NOTIFY_WOKENUP); 654 netlink_sendskb(info->notify_sock, info->notify_cookie); 655 break; 656 } 657 /* after notification unregisters process */ 658 put_pid(info->notify_owner); 659 put_user_ns(info->notify_user_ns); 660 info->notify_owner = NULL; 661 info->notify_user_ns = NULL; 662 } 663 wake_up(&info->wait_q); 664 } 665 666 static int prepare_timeout(const struct timespec __user *u_abs_timeout, 667 ktime_t *expires, struct timespec *ts) 668 { 669 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec))) 670 return -EFAULT; 671 if (!timespec_valid(ts)) 672 return -EINVAL; 673 674 *expires = timespec_to_ktime(*ts); 675 return 0; 676 } 677 678 static void remove_notification(struct mqueue_inode_info *info) 679 { 680 if (info->notify_owner != NULL && 681 info->notify.sigev_notify == SIGEV_THREAD) { 682 set_cookie(info->notify_cookie, NOTIFY_REMOVED); 683 netlink_sendskb(info->notify_sock, info->notify_cookie); 684 } 685 put_pid(info->notify_owner); 686 put_user_ns(info->notify_user_ns); 687 info->notify_owner = NULL; 688 info->notify_user_ns = NULL; 689 } 690 691 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr) 692 { 693 int mq_treesize; 694 unsigned long total_size; 695 696 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0) 697 return -EINVAL; 698 if (capable(CAP_SYS_RESOURCE)) { 699 if (attr->mq_maxmsg > HARD_MSGMAX || 700 attr->mq_msgsize > HARD_MSGSIZEMAX) 701 return -EINVAL; 702 } else { 703 if (attr->mq_maxmsg > ipc_ns->mq_msg_max || 704 attr->mq_msgsize > ipc_ns->mq_msgsize_max) 705 return -EINVAL; 706 } 707 /* check for overflow */ 708 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg) 709 return -EOVERFLOW; 710 mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) + 711 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) * 712 sizeof(struct posix_msg_tree_node); 713 total_size = attr->mq_maxmsg * attr->mq_msgsize; 714 if (total_size + mq_treesize < total_size) 715 return -EOVERFLOW; 716 return 0; 717 } 718 719 /* 720 * Invoked when creating a new queue via sys_mq_open 721 */ 722 static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir, 723 struct path *path, int oflag, umode_t mode, 724 struct mq_attr *attr) 725 { 726 const struct cred *cred = current_cred(); 727 int ret; 728 729 if (attr) { 730 ret = mq_attr_ok(ipc_ns, attr); 731 if (ret) 732 return ERR_PTR(ret); 733 /* store for use during create */ 734 path->dentry->d_fsdata = attr; 735 } else { 736 struct mq_attr def_attr; 737 738 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max, 739 ipc_ns->mq_msg_default); 740 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, 741 ipc_ns->mq_msgsize_default); 742 ret = mq_attr_ok(ipc_ns, &def_attr); 743 if (ret) 744 return ERR_PTR(ret); 745 } 746 747 mode &= ~current_umask(); 748 ret = vfs_create(dir, path->dentry, mode, true); 749 path->dentry->d_fsdata = NULL; 750 if (ret) 751 return ERR_PTR(ret); 752 return dentry_open(path, oflag, cred); 753 } 754 755 /* Opens existing queue */ 756 static struct file *do_open(struct path *path, int oflag) 757 { 758 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE, 759 MAY_READ | MAY_WRITE }; 760 int acc; 761 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) 762 return ERR_PTR(-EINVAL); 763 acc = oflag2acc[oflag & O_ACCMODE]; 764 if (inode_permission(d_inode(path->dentry), acc)) 765 return ERR_PTR(-EACCES); 766 return dentry_open(path, oflag, current_cred()); 767 } 768 769 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode, 770 struct mq_attr __user *, u_attr) 771 { 772 struct path path; 773 struct file *filp; 774 struct filename *name; 775 struct mq_attr attr; 776 int fd, error; 777 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 778 struct vfsmount *mnt = ipc_ns->mq_mnt; 779 struct dentry *root = mnt->mnt_root; 780 int ro; 781 782 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr))) 783 return -EFAULT; 784 785 audit_mq_open(oflag, mode, u_attr ? &attr : NULL); 786 787 if (IS_ERR(name = getname(u_name))) 788 return PTR_ERR(name); 789 790 fd = get_unused_fd_flags(O_CLOEXEC); 791 if (fd < 0) 792 goto out_putname; 793 794 ro = mnt_want_write(mnt); /* we'll drop it in any case */ 795 error = 0; 796 inode_lock(d_inode(root)); 797 path.dentry = lookup_one_len(name->name, root, strlen(name->name)); 798 if (IS_ERR(path.dentry)) { 799 error = PTR_ERR(path.dentry); 800 goto out_putfd; 801 } 802 path.mnt = mntget(mnt); 803 804 if (oflag & O_CREAT) { 805 if (d_really_is_positive(path.dentry)) { /* entry already exists */ 806 audit_inode(name, path.dentry, 0); 807 if (oflag & O_EXCL) { 808 error = -EEXIST; 809 goto out; 810 } 811 filp = do_open(&path, oflag); 812 } else { 813 if (ro) { 814 error = ro; 815 goto out; 816 } 817 audit_inode_parent_hidden(name, root); 818 filp = do_create(ipc_ns, d_inode(root), 819 &path, oflag, mode, 820 u_attr ? &attr : NULL); 821 } 822 } else { 823 if (d_really_is_negative(path.dentry)) { 824 error = -ENOENT; 825 goto out; 826 } 827 audit_inode(name, path.dentry, 0); 828 filp = do_open(&path, oflag); 829 } 830 831 if (!IS_ERR(filp)) 832 fd_install(fd, filp); 833 else 834 error = PTR_ERR(filp); 835 out: 836 path_put(&path); 837 out_putfd: 838 if (error) { 839 put_unused_fd(fd); 840 fd = error; 841 } 842 inode_unlock(d_inode(root)); 843 if (!ro) 844 mnt_drop_write(mnt); 845 out_putname: 846 putname(name); 847 return fd; 848 } 849 850 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name) 851 { 852 int err; 853 struct filename *name; 854 struct dentry *dentry; 855 struct inode *inode = NULL; 856 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 857 struct vfsmount *mnt = ipc_ns->mq_mnt; 858 859 name = getname(u_name); 860 if (IS_ERR(name)) 861 return PTR_ERR(name); 862 863 audit_inode_parent_hidden(name, mnt->mnt_root); 864 err = mnt_want_write(mnt); 865 if (err) 866 goto out_name; 867 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT); 868 dentry = lookup_one_len(name->name, mnt->mnt_root, 869 strlen(name->name)); 870 if (IS_ERR(dentry)) { 871 err = PTR_ERR(dentry); 872 goto out_unlock; 873 } 874 875 inode = d_inode(dentry); 876 if (!inode) { 877 err = -ENOENT; 878 } else { 879 ihold(inode); 880 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL); 881 } 882 dput(dentry); 883 884 out_unlock: 885 inode_unlock(d_inode(mnt->mnt_root)); 886 if (inode) 887 iput(inode); 888 mnt_drop_write(mnt); 889 out_name: 890 putname(name); 891 892 return err; 893 } 894 895 /* Pipelined send and receive functions. 896 * 897 * If a receiver finds no waiting message, then it registers itself in the 898 * list of waiting receivers. A sender checks that list before adding the new 899 * message into the message array. If there is a waiting receiver, then it 900 * bypasses the message array and directly hands the message over to the 901 * receiver. The receiver accepts the message and returns without grabbing the 902 * queue spinlock: 903 * 904 * - Set pointer to message. 905 * - Queue the receiver task for later wakeup (without the info->lock). 906 * - Update its state to STATE_READY. Now the receiver can continue. 907 * - Wake up the process after the lock is dropped. Should the process wake up 908 * before this wakeup (due to a timeout or a signal) it will either see 909 * STATE_READY and continue or acquire the lock to check the state again. 910 * 911 * The same algorithm is used for senders. 912 */ 913 914 /* pipelined_send() - send a message directly to the task waiting in 915 * sys_mq_timedreceive() (without inserting message into a queue). 916 */ 917 static inline void pipelined_send(struct wake_q_head *wake_q, 918 struct mqueue_inode_info *info, 919 struct msg_msg *message, 920 struct ext_wait_queue *receiver) 921 { 922 receiver->msg = message; 923 list_del(&receiver->list); 924 wake_q_add(wake_q, receiver->task); 925 /* 926 * Rely on the implicit cmpxchg barrier from wake_q_add such 927 * that we can ensure that updating receiver->state is the last 928 * write operation: As once set, the receiver can continue, 929 * and if we don't have the reference count from the wake_q, 930 * yet, at that point we can later have a use-after-free 931 * condition and bogus wakeup. 932 */ 933 receiver->state = STATE_READY; 934 } 935 936 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend() 937 * gets its message and put to the queue (we have one free place for sure). */ 938 static inline void pipelined_receive(struct wake_q_head *wake_q, 939 struct mqueue_inode_info *info) 940 { 941 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND); 942 943 if (!sender) { 944 /* for poll */ 945 wake_up_interruptible(&info->wait_q); 946 return; 947 } 948 if (msg_insert(sender->msg, info)) 949 return; 950 951 list_del(&sender->list); 952 wake_q_add(wake_q, sender->task); 953 sender->state = STATE_READY; 954 } 955 956 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr, 957 size_t, msg_len, unsigned int, msg_prio, 958 const struct timespec __user *, u_abs_timeout) 959 { 960 struct fd f; 961 struct inode *inode; 962 struct ext_wait_queue wait; 963 struct ext_wait_queue *receiver; 964 struct msg_msg *msg_ptr; 965 struct mqueue_inode_info *info; 966 ktime_t expires, *timeout = NULL; 967 struct timespec ts; 968 struct posix_msg_tree_node *new_leaf = NULL; 969 int ret = 0; 970 WAKE_Q(wake_q); 971 972 if (u_abs_timeout) { 973 int res = prepare_timeout(u_abs_timeout, &expires, &ts); 974 if (res) 975 return res; 976 timeout = &expires; 977 } 978 979 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX)) 980 return -EINVAL; 981 982 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL); 983 984 f = fdget(mqdes); 985 if (unlikely(!f.file)) { 986 ret = -EBADF; 987 goto out; 988 } 989 990 inode = file_inode(f.file); 991 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 992 ret = -EBADF; 993 goto out_fput; 994 } 995 info = MQUEUE_I(inode); 996 audit_file(f.file); 997 998 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) { 999 ret = -EBADF; 1000 goto out_fput; 1001 } 1002 1003 if (unlikely(msg_len > info->attr.mq_msgsize)) { 1004 ret = -EMSGSIZE; 1005 goto out_fput; 1006 } 1007 1008 /* First try to allocate memory, before doing anything with 1009 * existing queues. */ 1010 msg_ptr = load_msg(u_msg_ptr, msg_len); 1011 if (IS_ERR(msg_ptr)) { 1012 ret = PTR_ERR(msg_ptr); 1013 goto out_fput; 1014 } 1015 msg_ptr->m_ts = msg_len; 1016 msg_ptr->m_type = msg_prio; 1017 1018 /* 1019 * msg_insert really wants us to have a valid, spare node struct so 1020 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will 1021 * fall back to that if necessary. 1022 */ 1023 if (!info->node_cache) 1024 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); 1025 1026 spin_lock(&info->lock); 1027 1028 if (!info->node_cache && new_leaf) { 1029 /* Save our speculative allocation into the cache */ 1030 INIT_LIST_HEAD(&new_leaf->msg_list); 1031 info->node_cache = new_leaf; 1032 new_leaf = NULL; 1033 } else { 1034 kfree(new_leaf); 1035 } 1036 1037 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) { 1038 if (f.file->f_flags & O_NONBLOCK) { 1039 ret = -EAGAIN; 1040 } else { 1041 wait.task = current; 1042 wait.msg = (void *) msg_ptr; 1043 wait.state = STATE_NONE; 1044 ret = wq_sleep(info, SEND, timeout, &wait); 1045 /* 1046 * wq_sleep must be called with info->lock held, and 1047 * returns with the lock released 1048 */ 1049 goto out_free; 1050 } 1051 } else { 1052 receiver = wq_get_first_waiter(info, RECV); 1053 if (receiver) { 1054 pipelined_send(&wake_q, info, msg_ptr, receiver); 1055 } else { 1056 /* adds message to the queue */ 1057 ret = msg_insert(msg_ptr, info); 1058 if (ret) 1059 goto out_unlock; 1060 __do_notify(info); 1061 } 1062 inode->i_atime = inode->i_mtime = inode->i_ctime = 1063 current_time(inode); 1064 } 1065 out_unlock: 1066 spin_unlock(&info->lock); 1067 wake_up_q(&wake_q); 1068 out_free: 1069 if (ret) 1070 free_msg(msg_ptr); 1071 out_fput: 1072 fdput(f); 1073 out: 1074 return ret; 1075 } 1076 1077 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr, 1078 size_t, msg_len, unsigned int __user *, u_msg_prio, 1079 const struct timespec __user *, u_abs_timeout) 1080 { 1081 ssize_t ret; 1082 struct msg_msg *msg_ptr; 1083 struct fd f; 1084 struct inode *inode; 1085 struct mqueue_inode_info *info; 1086 struct ext_wait_queue wait; 1087 ktime_t expires, *timeout = NULL; 1088 struct timespec ts; 1089 struct posix_msg_tree_node *new_leaf = NULL; 1090 1091 if (u_abs_timeout) { 1092 int res = prepare_timeout(u_abs_timeout, &expires, &ts); 1093 if (res) 1094 return res; 1095 timeout = &expires; 1096 } 1097 1098 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL); 1099 1100 f = fdget(mqdes); 1101 if (unlikely(!f.file)) { 1102 ret = -EBADF; 1103 goto out; 1104 } 1105 1106 inode = file_inode(f.file); 1107 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1108 ret = -EBADF; 1109 goto out_fput; 1110 } 1111 info = MQUEUE_I(inode); 1112 audit_file(f.file); 1113 1114 if (unlikely(!(f.file->f_mode & FMODE_READ))) { 1115 ret = -EBADF; 1116 goto out_fput; 1117 } 1118 1119 /* checks if buffer is big enough */ 1120 if (unlikely(msg_len < info->attr.mq_msgsize)) { 1121 ret = -EMSGSIZE; 1122 goto out_fput; 1123 } 1124 1125 /* 1126 * msg_insert really wants us to have a valid, spare node struct so 1127 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will 1128 * fall back to that if necessary. 1129 */ 1130 if (!info->node_cache) 1131 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); 1132 1133 spin_lock(&info->lock); 1134 1135 if (!info->node_cache && new_leaf) { 1136 /* Save our speculative allocation into the cache */ 1137 INIT_LIST_HEAD(&new_leaf->msg_list); 1138 info->node_cache = new_leaf; 1139 } else { 1140 kfree(new_leaf); 1141 } 1142 1143 if (info->attr.mq_curmsgs == 0) { 1144 if (f.file->f_flags & O_NONBLOCK) { 1145 spin_unlock(&info->lock); 1146 ret = -EAGAIN; 1147 } else { 1148 wait.task = current; 1149 wait.state = STATE_NONE; 1150 ret = wq_sleep(info, RECV, timeout, &wait); 1151 msg_ptr = wait.msg; 1152 } 1153 } else { 1154 WAKE_Q(wake_q); 1155 1156 msg_ptr = msg_get(info); 1157 1158 inode->i_atime = inode->i_mtime = inode->i_ctime = 1159 current_time(inode); 1160 1161 /* There is now free space in queue. */ 1162 pipelined_receive(&wake_q, info); 1163 spin_unlock(&info->lock); 1164 wake_up_q(&wake_q); 1165 ret = 0; 1166 } 1167 if (ret == 0) { 1168 ret = msg_ptr->m_ts; 1169 1170 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) || 1171 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) { 1172 ret = -EFAULT; 1173 } 1174 free_msg(msg_ptr); 1175 } 1176 out_fput: 1177 fdput(f); 1178 out: 1179 return ret; 1180 } 1181 1182 /* 1183 * Notes: the case when user wants us to deregister (with NULL as pointer) 1184 * and he isn't currently owner of notification, will be silently discarded. 1185 * It isn't explicitly defined in the POSIX. 1186 */ 1187 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes, 1188 const struct sigevent __user *, u_notification) 1189 { 1190 int ret; 1191 struct fd f; 1192 struct sock *sock; 1193 struct inode *inode; 1194 struct sigevent notification; 1195 struct mqueue_inode_info *info; 1196 struct sk_buff *nc; 1197 1198 if (u_notification) { 1199 if (copy_from_user(¬ification, u_notification, 1200 sizeof(struct sigevent))) 1201 return -EFAULT; 1202 } 1203 1204 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL); 1205 1206 nc = NULL; 1207 sock = NULL; 1208 if (u_notification != NULL) { 1209 if (unlikely(notification.sigev_notify != SIGEV_NONE && 1210 notification.sigev_notify != SIGEV_SIGNAL && 1211 notification.sigev_notify != SIGEV_THREAD)) 1212 return -EINVAL; 1213 if (notification.sigev_notify == SIGEV_SIGNAL && 1214 !valid_signal(notification.sigev_signo)) { 1215 return -EINVAL; 1216 } 1217 if (notification.sigev_notify == SIGEV_THREAD) { 1218 long timeo; 1219 1220 /* create the notify skb */ 1221 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL); 1222 if (!nc) { 1223 ret = -ENOMEM; 1224 goto out; 1225 } 1226 if (copy_from_user(nc->data, 1227 notification.sigev_value.sival_ptr, 1228 NOTIFY_COOKIE_LEN)) { 1229 ret = -EFAULT; 1230 goto out; 1231 } 1232 1233 /* TODO: add a header? */ 1234 skb_put(nc, NOTIFY_COOKIE_LEN); 1235 /* and attach it to the socket */ 1236 retry: 1237 f = fdget(notification.sigev_signo); 1238 if (!f.file) { 1239 ret = -EBADF; 1240 goto out; 1241 } 1242 sock = netlink_getsockbyfilp(f.file); 1243 fdput(f); 1244 if (IS_ERR(sock)) { 1245 ret = PTR_ERR(sock); 1246 sock = NULL; 1247 goto out; 1248 } 1249 1250 timeo = MAX_SCHEDULE_TIMEOUT; 1251 ret = netlink_attachskb(sock, nc, &timeo, NULL); 1252 if (ret == 1) 1253 goto retry; 1254 if (ret) { 1255 sock = NULL; 1256 nc = NULL; 1257 goto out; 1258 } 1259 } 1260 } 1261 1262 f = fdget(mqdes); 1263 if (!f.file) { 1264 ret = -EBADF; 1265 goto out; 1266 } 1267 1268 inode = file_inode(f.file); 1269 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1270 ret = -EBADF; 1271 goto out_fput; 1272 } 1273 info = MQUEUE_I(inode); 1274 1275 ret = 0; 1276 spin_lock(&info->lock); 1277 if (u_notification == NULL) { 1278 if (info->notify_owner == task_tgid(current)) { 1279 remove_notification(info); 1280 inode->i_atime = inode->i_ctime = current_time(inode); 1281 } 1282 } else if (info->notify_owner != NULL) { 1283 ret = -EBUSY; 1284 } else { 1285 switch (notification.sigev_notify) { 1286 case SIGEV_NONE: 1287 info->notify.sigev_notify = SIGEV_NONE; 1288 break; 1289 case SIGEV_THREAD: 1290 info->notify_sock = sock; 1291 info->notify_cookie = nc; 1292 sock = NULL; 1293 nc = NULL; 1294 info->notify.sigev_notify = SIGEV_THREAD; 1295 break; 1296 case SIGEV_SIGNAL: 1297 info->notify.sigev_signo = notification.sigev_signo; 1298 info->notify.sigev_value = notification.sigev_value; 1299 info->notify.sigev_notify = SIGEV_SIGNAL; 1300 break; 1301 } 1302 1303 info->notify_owner = get_pid(task_tgid(current)); 1304 info->notify_user_ns = get_user_ns(current_user_ns()); 1305 inode->i_atime = inode->i_ctime = current_time(inode); 1306 } 1307 spin_unlock(&info->lock); 1308 out_fput: 1309 fdput(f); 1310 out: 1311 if (sock) 1312 netlink_detachskb(sock, nc); 1313 else if (nc) 1314 dev_kfree_skb(nc); 1315 1316 return ret; 1317 } 1318 1319 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes, 1320 const struct mq_attr __user *, u_mqstat, 1321 struct mq_attr __user *, u_omqstat) 1322 { 1323 int ret; 1324 struct mq_attr mqstat, omqstat; 1325 struct fd f; 1326 struct inode *inode; 1327 struct mqueue_inode_info *info; 1328 1329 if (u_mqstat != NULL) { 1330 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr))) 1331 return -EFAULT; 1332 if (mqstat.mq_flags & (~O_NONBLOCK)) 1333 return -EINVAL; 1334 } 1335 1336 f = fdget(mqdes); 1337 if (!f.file) { 1338 ret = -EBADF; 1339 goto out; 1340 } 1341 1342 inode = file_inode(f.file); 1343 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1344 ret = -EBADF; 1345 goto out_fput; 1346 } 1347 info = MQUEUE_I(inode); 1348 1349 spin_lock(&info->lock); 1350 1351 omqstat = info->attr; 1352 omqstat.mq_flags = f.file->f_flags & O_NONBLOCK; 1353 if (u_mqstat) { 1354 audit_mq_getsetattr(mqdes, &mqstat); 1355 spin_lock(&f.file->f_lock); 1356 if (mqstat.mq_flags & O_NONBLOCK) 1357 f.file->f_flags |= O_NONBLOCK; 1358 else 1359 f.file->f_flags &= ~O_NONBLOCK; 1360 spin_unlock(&f.file->f_lock); 1361 1362 inode->i_atime = inode->i_ctime = current_time(inode); 1363 } 1364 1365 spin_unlock(&info->lock); 1366 1367 ret = 0; 1368 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat, 1369 sizeof(struct mq_attr))) 1370 ret = -EFAULT; 1371 1372 out_fput: 1373 fdput(f); 1374 out: 1375 return ret; 1376 } 1377 1378 static const struct inode_operations mqueue_dir_inode_operations = { 1379 .lookup = simple_lookup, 1380 .create = mqueue_create, 1381 .unlink = mqueue_unlink, 1382 }; 1383 1384 static const struct file_operations mqueue_file_operations = { 1385 .flush = mqueue_flush_file, 1386 .poll = mqueue_poll_file, 1387 .read = mqueue_read_file, 1388 .llseek = default_llseek, 1389 }; 1390 1391 static const struct super_operations mqueue_super_ops = { 1392 .alloc_inode = mqueue_alloc_inode, 1393 .destroy_inode = mqueue_destroy_inode, 1394 .evict_inode = mqueue_evict_inode, 1395 .statfs = simple_statfs, 1396 }; 1397 1398 static struct file_system_type mqueue_fs_type = { 1399 .name = "mqueue", 1400 .mount = mqueue_mount, 1401 .kill_sb = kill_litter_super, 1402 .fs_flags = FS_USERNS_MOUNT, 1403 }; 1404 1405 int mq_init_ns(struct ipc_namespace *ns) 1406 { 1407 ns->mq_queues_count = 0; 1408 ns->mq_queues_max = DFLT_QUEUESMAX; 1409 ns->mq_msg_max = DFLT_MSGMAX; 1410 ns->mq_msgsize_max = DFLT_MSGSIZEMAX; 1411 ns->mq_msg_default = DFLT_MSG; 1412 ns->mq_msgsize_default = DFLT_MSGSIZE; 1413 1414 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns); 1415 if (IS_ERR(ns->mq_mnt)) { 1416 int err = PTR_ERR(ns->mq_mnt); 1417 ns->mq_mnt = NULL; 1418 return err; 1419 } 1420 return 0; 1421 } 1422 1423 void mq_clear_sbinfo(struct ipc_namespace *ns) 1424 { 1425 ns->mq_mnt->mnt_sb->s_fs_info = NULL; 1426 } 1427 1428 void mq_put_mnt(struct ipc_namespace *ns) 1429 { 1430 kern_unmount(ns->mq_mnt); 1431 } 1432 1433 static int __init init_mqueue_fs(void) 1434 { 1435 int error; 1436 1437 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache", 1438 sizeof(struct mqueue_inode_info), 0, 1439 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once); 1440 if (mqueue_inode_cachep == NULL) 1441 return -ENOMEM; 1442 1443 /* ignore failures - they are not fatal */ 1444 mq_sysctl_table = mq_register_sysctl_table(); 1445 1446 error = register_filesystem(&mqueue_fs_type); 1447 if (error) 1448 goto out_sysctl; 1449 1450 spin_lock_init(&mq_lock); 1451 1452 error = mq_init_ns(&init_ipc_ns); 1453 if (error) 1454 goto out_filesystem; 1455 1456 return 0; 1457 1458 out_filesystem: 1459 unregister_filesystem(&mqueue_fs_type); 1460 out_sysctl: 1461 if (mq_sysctl_table) 1462 unregister_sysctl_table(mq_sysctl_table); 1463 kmem_cache_destroy(mqueue_inode_cachep); 1464 return error; 1465 } 1466 1467 device_initcall(init_mqueue_fs); 1468